We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Calcium current activated by potassium ions in voltage-clamped rat hippocampal pyramidal neurones.
- Authors
Deák, Ferenc; Nagy, Gábor; Várnai, Péter; Madarász, Emília; Spät, András
- Abstract
Neuronal activity results in local elevation of extracellular K+ concentration ([K+]o)., Using the patch-clamp technique in the whole-cell configuration, we investigated whether extracellular K+ activates non-voltage-operated Ca2+ channels in pyramidal cells cultured from rat embryonic hippocampi., K+ (12 mM) reversibly activated a sustained inward current at a holding potential of -100 mV. Membrane conductance and variance of noise were significantly increased by K+. This current could be observed at membrane potentials negative to +60 mV., Inhibitors of inward rectifier K+ channels and hyperpolarization-induced cation current reduced the current only at potentials negative to -50 mV., The K+-induced current was activated in Na+-free but not in Ca2+-free medium, did not depend on cytosolic [Cl−], and was blocked by Cd2+ but not by organic channel inhibitors., Half-maximal activation of the current (at -100 mV) was attained at [K+]o≈ 20 mM., The current is similar to Igl, a K+-induced Ca2+ current described in glomerulosa cells. It was also present in pyramidal cells from prefrontal cortex but not in hippocampal bipolar and glial cells., Activation of K+-induced Ca2+ current may elevate cytoplasmic [Ca2+] at [K+]o levels which are insufficent to activate voltage-dependent Ca2+ channels.
- Publication
Journal of Physiology, 1998, Vol 508, Issue 3, p735
- ISSN
0022-3751
- Publication type
Article
- DOI
10.1111/j.1469-7793.1998.735bp.x